This disclosure is in the field of electric power distribution. The disclosed embodiments are directed to power converters and systems of power converters capable of receiving power from various types of power sources.
The generation of electrical power from renewable energy sources such as solar, wind, water, and geothermal has become more popular in recent years. Solar and wind energy have become especially attractive in providing electrical power to loads near the generation site, such as at cellular telephone towers, telecommunication central offices, home or business locations that are independent from the electrical power grid, and the like. However, as well known in the art, the electrical power generated by solar and wind-generated electrical power will fluctuate over time (e.g., day vs. night for solar power), and in response to weather and other environmental conditions.
To reduce the expense of metered power from the AC grid, and also to reduce environmental impact, it is often desirable to use power from renewable sources such as solar cell arrays, wind-powered generators, and the like when that power is available. This preference is especially useful at remote or otherwise self-contained installations of both a renewable power source and the load powered by that power source, such as at cell towers. However, the power generated by different types of power sources, particularly renewable sources, exhibit different attributes from one another. These differences render it difficult to arrive at a power converter architecture that can optimally and efficiently convert power from this wide array of input power sources.
In some situations, power converters supplying power from renewable power sources are deployed at locations that are remote from the AC electrical grid. For example, a mobile communications base station site may be deployed at a rural or backwoods location, prohibitively far from the electrical grid. In those situations, excess power from the renewable power source can be supplied to the grid through an inverter, if available. In the absence of such an expensive system the excessive power cannot be harvested to prevent damage to the power converter system. This situation is exacerbated if the power demand by the load is variable, and if a battery backup system is not present or if the batteries are fully charged.